SPL Set ID: 2a2238e9-4b5d-c56d-8663-dd354ff9ae0c

The system contains fentanyl, an opioid agonist, for transdermal administration. The amount of fentanyl released from each system per hour is proportional to the surface area (25 mcg/hour per 6.25 cm 2 ). The composition per unit area of all transdermal system sizes is identical. Strength (mcg/hour) Size (cm 2 ) Fentanyl Content (mg) 12 Nominal delivery rate is 12.5 mcg/hour 3.13 1.28 25 Nominal delivery rate per hour 6.25 2.55 37.5 9.38 3.83 50 12.5 5.10 62.5 15.63 6.38 75 18.75 7.65 87.5 21.88 8.93 100 25 10.20 The molecular weight of fentanyl base is 336.5, and the molecular formula is C 22 H 28 N 2 O. The n‑octanol: water partition coefficient is 860:1. The pKa is 8.4. The chemical name is N-Phenyl-N-[1-(2-phenylethyl)-4-piperidinyl] propanamide. The structural formula is: Fentanyl transdermal system is a rectangular translucent system with rounded corners. “Fentanyl”, dosage strength and diagonal lines are printed in blue ink on each system. Each system is comprised of a polyester release liner and two functional layers. Proceeding from the outer surface toward the surface adhering to skin, these functional layers are: 1) a backing layer of translucent polyolefin film with blue print; 2) a drug-in-adhesive layer containing fentanyl as the active ingredient and dimethicone NF and silicone adhesive as inactive ingredients. Before use, a polyester release liner covering the drug-in-adhesive layer is removed and discarded. Fentanyl transdermal systems are packaged with additional pieces of protective film above and below the system within each pouch. These are discarded at the time of use. Fentanyl Structural Formula Parts of the Fentanyl Transdermal System